The present invention is directed to an improvement in a device for safely protecting fixed structures from damage resulting from colliding vehicles or the like. More particularly, this invention is directed to an improved fender panel for a reusable impact attenuation device for absorbing and harmlessly dissipating the impact energy of a colliding vehicle.
It is known that rigid guardrails and similar immovable protective devices alongside vehicular traffic routes such as highspeed highways may be used for the purpose of preventing vehicles from colliding with fixed structures such as, for example, abutments, columns, and sign supports. A common practice is to place a rigid railing between the vehicular traffic route and the fixed structure to deflect the vehicle in such a manner that the vehicle avoids direct impact with the fixed structure. Such devices are of only limited value since they do not decelerate the vehicle at a controlled, safe rate to provide maximum safety and minimum injury to the occupants of the impacting vehicle. Further, such devices result in the impacting vehicle being thrown back onto the highway into the path of other moving vehicles.
It is also known that an improved and reusable impact attenuation device for protecting stationary structures from damage due to impacting vehicles can be provided utilizing an array of energy absorbing buffer elements arranged in chambers which sandwich or telescope into each other upon impact. Such chambers can be formed partially by fender panels which extend rearwardly in their normal positions to aid in properly redirecting a vehicle after a lateral impact to the protective device. U.S. Pat. Nos. 3,674,115 and 3,944,187 disclose such reusable impact attenuation devices having liquid and solid buffer elements, respectively.
Although the reusable impact attenuation devices of U.S. Pat. Nos. 3,674,115 and 3,944,187 have greatly advanced the art and have gained wide acceptance and recognition, occasional difficulties have arisen following an impact. More specifically, the fender panels may become dislodged from their normal positions by a direct impact to one of the impact attenuation devices. As a result, the fender panels as well as the support structure of the impact attenuation device may have an increased risk of damage due to wind or other causes until the impact attenuation device is serviced to restore its initial condition. Further, the dislodged fender panels may limit the ability of the impact attenuation device to function if a second impact occurs before the device is serviced.
It is known that the fender panels may be hinged to laterally extending diaphragm members and may be biased inward by springs connecting the free end of each of the fender panels to the diaphragm member adjacent the free end of the fender panel. However, such springs may permit the fender panels to flap in response to a strong gust of wind. Further, such springs may be stretched beyond their elastic limits during a severe impact and may have a reduced biasing effect when the distance between the diaphragm members is foreshortened as the chambers telescope. A need exists for an improved reusable impact attenuation device in which the fender panels are held in their normal positions before an impact and are returned to their following a severe impact, even if the distance between the diaphragm members is foreshortened.
Accordingly, it is an object of this invention to provide a restorable fender panel for a reusable impact attenuation device such that the fender panel is held tightly against the overlapped adjacent fender panel until an impact and is restored to that normal position immediately following an impact, even if the chambers have telescoped during the impact.